The present invention concerns the preparation of aromatic polyamines in the presence of ion exchange resins as catalyst.
The technique of using ion exchange resins as catalysts for preparing aromatic polyamines has been disclosed in Canadian Pat. No. 895,915 issued to Kaiser Aluminum and Chemical Corporation and in European Patent Application publication No. 0,000,778 by Bayer AG. Such catalysts are operable over relatively long periods of time in batch operations. Howver, when the processes are modified to employ such ion exchange resin catalysts by conventional means in continuous processes using plug flow type reactors, they tend to lose their reactivity in a relatively short period of time.
The present invention, therefore, describes a process whereby ion exchange resin catalysts can be employed over extended periods of time.